The microactuators are miniaturized objects produced in solid supports that may be semiconductors or insulators, for the purpose of forming microsystems such as, for example, microvalves or micropumps in fluid microcircuits, or microswitches in electronic microcircuits.
Microactuators using electrostatic, piezoelectric, electromagnetic and bimetallic effects have already existed for quite a long time. A new generation of microactuators is starting to appear, namely those using a pyrotechnic effect. Pyrotechnic materials have a high energy density, and their use in microactuators therefore makes it possible for the dimensions of microsystems incorporating such microactuators to be considerably reduced. Such pyrotechnic microactuators are described for example in patent application WO 02/088551.
As is known, a pyrotechnic microactuator is operated by causing the combustion of a pyrotechnic microcharge, generally by locally raising its temperature up to a decomposition threshold by means of an initiation device. There may be a large number of microactuators integrated into the same microsystem, for example several hundred microactuators. Since each microactuator possesses its own initiation device, the question arises as how to individually address each of the microactuators. The system for individually initiating each of the microactuators may be entirely integrated into the microsystem. However, the microsystem therefore becomes much more complex. In addition, it should be recalled that a pyrotechnic microactuator operates in “single shot” mode, the combustion of a pyrotechnic microcharge being irreversible. The application of such pyrotechnic microactuators will therefore be implemented as a general rule in consumable products that are used only once. In order for such single-use products to be commercially viable they will therefore have to have a relatively low manufacturing cost. The use of an initiation device integrated into the microsystem will therefore not only make the final product complex, but it will also considerably increase its manufacturing cost.